1. Field of the Invention
The present invention relates to ink-jet, heat-transfer media that are coated with certain ink-receptive coatings. An ink-jet printer can be used to print an image on the heat-transfer medium, and the printed image can be heat-transferred to a fabric material.
2. Brief Description of the Related Art
Ink-jet printers are used commonly today in a wide variety of printing applications. Most inks used in ink-jet printers are aqueous-based inks containing water as their primary component. These aqueous-based inks contain molecular dyes and/or pigmented colorants. Small amounts of water-miscible solvents such as glycols and glycol ethers can also be present. The intended medium for receiving the ink (e.g., a paper or film) can be coated with an ink-receptive composition in the manufacturing of the medium. A conventional ink-jet printer can be used to print an image onto the coated medium. During the printing step, dyes or colorants from the ink can penetrate into the ink-receptive coating on the medium. Then, water and other solvents, if present, can evaporate from the printed medium as the medium is dried.
The ink-jet media industry continuously devotes research efforts to developing new ink-receptive coatings. A primary research goal is to make a coated medium that accepts and holds the ink so that a good quality image is recorded on the medium. Producing colored images having high color brightness and vibrancy are key objectives. Moreover, it is important that the quality of the image be maintained after the image is exposed to water and other liquids. These properties are particularly important for ink-jet, heat-transfer papers that are used to create images on fabric substrates such as tee-shirts.
In recent years, there has been a growing interest in using ink-jet, heat-transfer media to transfer images (e.g., photos, text, illustrations, graphic designs, and the like) to tee-shirts, sweatshirts, and other fabric materials. Consumers have found these products easy to use with conventional desktop computers and printers to create personalized designs on clothing. Generally, the process involves using a desktop computer to generate a computerized image and sending it to an ink-jet printer that uses aqueous-based ink to print the image onto a heat-transfer paper. Then, the printed image can be heat-transferred from the paper to a receptor fabric substrate, e.g. tee-shirt, using a heating means such as a hand iron or heat press. Commercially-available ink-jet, heat-transfer papers typically comprise a support paper having a surface coated with an ink-receptive layer for recording the printed image on the paper.
In many instances, the coated ink-receptive layer used for such heat-transfer papers comprises particles of a thermoplastic polymer and a film-forming binder. The polymer particles and film-forming binder form a porous coating structure that absorbs the aqueous ink vehicle (water). As ink is impinged onto the porous coating in the ink-jet printing step, it can enter interstitial voids and spaces in the coating structure.
For example, Kronzer, U.S. Pat. No. 5,242,739 discloses an image-receptive, heat-transfer paper which includes: (a) a flexible cellulosic non-woven web base sheet; and (b) an image-receptive melt-transfer film layer overlaying the base sheet. The film layer is composed of from about 15 to 80 percent by weight of a film-forming binder and from about 85 to about 20 percent by weight of a powdered thermoplastic polymer. The powdered thermoplastic polymer is preferably selected from the group consisting of polyolefins, polyesters, and ethylene-vinyl acetate copolymers.
Kronzer, U.S. Pat. No. 5,271,990 discloses an image-receptive, heat-transfer paper coated with an image-receptive, melt-transfer film layer having a Sheffield Smoothness of about 10 cc/minute. The image-receptive film layer overlays the base sheet. The image-receptive layer comprises a film-forming binder and particles of a thermoplastic polymer. Preferably, the thermoplastic polymer particles are selected from the group consisting of polyolefins, polyesters, and ethylene-vinyl acetate copolymers.
Kronzer, U.S. Pat. No. 5,501,902 discloses ink-jet printable, heat-transfer materials having a first layer (e.g., film or paper), and a second layer overlaying the first layer. The second layer comprises a film-forming binder such as a polyacrylate, polyethylene, or ethylene-vinyl acetate copolymer, and particles of a thermoplastic polymer having dimensions of less than 50 micrometers. According to the '902 patent, the powdered thermoplastic polymer is desirably selected from the group consisting of polyolefins, polyesters, and ethylene-vinyl acetate copolymers. Further, the second layer may comprise a cationic polymer (e.g., an amide-epichlorohydrin polymer), a humectant (e.g., ethylene glycol or polyethylene glycol), ink-viscosity modifier (e.g., polyethylene glycol), a weak acid (e.g., citric acid), and/or a surfactant.
Kronzer, U.S. Pat. No. 5,798,179 discloses ink-jet printable, heat-transfer papers having cold release properties. The heat-transfer paper is coated with multiple layers comprising particles of thermoplastic polymers and film-forming binders. The '179 patent discloses that the fourth layer is useful for recording images from inkjet printers and contains a film-forming binder and thermoplastic polymer particles selected from the group consisting of polyolefins, polyesters, polyamides, and ethylene-vinyl acetate copolymers.
Sato et al., U.S. Pat. No. 6,139,672 discloses an ink-jet recording medium for transfer printing images onto fabrics. The medium comprises a base material, a releasing layer, and a transfer layer. The transfer layer contains fine particles of a thermoplastic resin, a thermoplastic resin binder, a cationic resin, and inorganic fine particles. Fine particles of polyethylene, polypropylene, poly(meth)acrylic acid, poly(meth)acrylates, polyvinyl acetate, polyvinyl chloride, polyurethane, polyamide and copolymers thereof are more preferably used according to the '672 patent.
Bamberg et al., U.S. Pat. No. 6,638,604 discloses an ink-jet transfer system for applying graphic presentations, patterns, images, or typing onto light-colored clothing articles. The ink-jet transfer system comprises a carrier material (e.g., a silicone-coated or non-coated paper), a hot-melt layer overlaying the carrier material, and an ink-receiving layer overlaying the hot-melt layer. The hot-melt layer may comprise a dispersion of an ethylene/acrylic acid copolymer. The ink-receiving layer may comprise a polyamide binder and a highly porous polyamide pigment.
Although some conventional ink-jet, heat-transfer media products can effectively produce images having generally good color print quality on fabric substrates, there is still a need for an improved heat-transfer medium capable of generating images having improved color vibrancy and brightness.
In addition, many known ink-jet, heat-transfer media products produce images have a rough “hand” on the fabric. The “hand” of the printed image on the fabric refers to the tactile qualities of the imaged fabric, particularly the softness or hardness of the image after it has been transferred to the fabric. Printed images on the fabric having a soft and smooth feel are more desirable over hard and rough printed images. There is a need for an improved heat-transfer medium that will produce images having a softer hand on the fabric.
Furthermore, there is a need for heat-transfer media that can produce images having improved wash-durability. Wash-durability is a particular problem with many conventional heat-transfer papers. When such heat-transfer papers are used, the transferred image may develop cracks and colors may fade after repeated washings and dryings of the fabric. In view of the foregoing problems with conventional ink-jet, heat-transfer papers, there is a need for an improved heat-transfer paper capable of providing printed images having improved color quality, hand, and wash-durability on fabric materials. The present invention provides such a heat-transfer paper. These and other objects, features, and advantages of this invention are evident from the following description.